Sulfolobus

RR spectra of the Rieske protein from T. thermophilus (TRP) and of phthalate dioxygenase from Burkholderia cepacia (PDO) have been reported by Kuila et al. (66, 67), and those of the Rieske protein from Sulfolobus sp. strain 7 tentatively called sulredoxin by Iwasaki et al. (68). Although no complete analysis is yet available, several conclusions can be drawn from these spectra, in comparison to the spectra of proteins containing a 4-cysteine coordinated [2Fe-2S] cluster (Table VI). 

The Rieske protein II (SoxF) from Sulfolobus acidocaldarius, which is part, not of a bci or b f complex, but of the SoxM oxidase complex 18), could be expressed in E. coli, both in a full-length form containing the membrane anchor and in truncated water-soluble forms 111). In contrast to the results reported for the Rieske protein from Rhodobacter sphaeroides, the Rieske cluster was more efficiently inserted into the truncated soluble forms of the protein. Incorporation of the cluster was increased threefold when the E. coli cells were subject to a heat shock (42°C for 30 min) before induction of the expression of the Rieske protein, indicating that chaperonins facilitate the correct folding of the soluble form of SoxF. The iron content of the purified soluble SoxF variant was calculated as 1.5 mol Fe/mol protein the cluster showed g values very close to those observed in the SoxM complex and a redox potential of E° = +375 mV 111). 

In summary, it appears that the protein has to adopt the correct fold before the Rieske cluster can be inserted. The correct folding will depend on the stability of the protein the Rieske protein from the thermoacidophilic archaebacterium Sulfolobus seems to be more stable than Rieske proteins from other bacteria so that the Rieske cluster can be inserted into the soluble form of the protein during expression with the help of the chaperonins. If the protein cannot adopt the correct fold, the result will be either no cluster or a distorted iron sulfur cluster, perhaps using the two cysteines that form the disulfide bridge in correctly assembled Rieske proteins. 

To date, only two exceptions to the pK of 8 rule have been found the Rieske protein from Sulfolobus acidocaldarius (139) and that from Thiobacillus ferrooxidans (140). In both cases, a first pK is observed in the vicinity of 6 (Fig. 7). The fact that Sulfolobus and Thiobacillus are phylogenetically almost as distant as they can possibly be, but share acidophilic growth conditions (medium-pH of 2), indicates that the pK, which is lower by 2 pH units in Sulfolobus and Thiobacillus, reflects adaptation. In the absence of structural information for the two acidophilic Rieske proteins, the molecular modifications resulting in this pK shift are difficult to guess. The absence of sequence data for the Thiobacillus protein furthermore precludes a comparative approach. It seems likely, however, that the solvent-exposed histidine ligands to the cluster will become slightly more bur-... 

Remonsellez F, A Orell, CA Jerez (2006) Copper tolerance of the thermoacidophilic archaeon Sulfolobus metallicus possible role of polyphosphate metabolism. Microbiology (UK) 152 59-66. 

Cacciapuoti G, M Porcelli, M de Rosa, A Gambacorta, C Bertoldo, V Zappia (1991) 5 -adenosylmethionine decarboxylase from the thermophilic archaebacterium Sulfolobus solfataricus. Putification, molecular properties and studies on the covalently bound pyruvate. Eur J Biochem 199 395-400. 

In the leaching process, bacteria such as Thiobacillus ferroxidans and those belonging to the Sulfolobus genera, play a major role in the oxidation reactions at moderate and higher temperatures respectively. The oxidation of sulfides by bacteria is typified by the reactions of pyrite, a common accessory mineral in primary copper ore bodies this reaction can be considered to proceed through two stages ... 

Albers, S.V., Jonuscheit, M., Dinkelaker, S. et al. (2006) Production of recombinant and tagged proteins in the hyperthermophilic archaeon Sulfolobus solfataricus. Applied and Environmental Microbiology, 72 (1), 102-111. 

Kargi, F., and Robinson, J. M., Microbial Oxidation of Dibenzothiophene by the Thermophilic Organism Sulfolobus Acidocaldarius. Biotechnology and Bioengineering, 1984. 26 p. 687. 

Kankipati, P., and Ju, L. K., Microbial Desulfurization of Petroleum Fundamental Study on Dibenzothiophene Desulfurization by Sulfolobus Acidocaldarius. In Exploration Issues and Solutions in Petroleum Exploration, Production and Refining. 1994. Pennwell Books. 605-614. 

Sulfolobus (archaea) Use sulfur as an energy source thermophile and acidophile... 

The transesterification of phenyl-/J-D-glucoside catalyzed by Sulfolobus solfataricus [81b] was quantitative within 2 h at 110 °C under the action of irradiation whereas the yield was only 60% after 40 h under classical conditions (Scheme 8.57). 

---